1. Field of the Invention
The present invention relates to a connection confirmation system and method for an expansion unit used in a computer, which can be connected to the expansion unit via, e.g., an expansion bus connector, and has a resume function.
2. Description of the Related Art
In a conventional lap-top type compact portable computer having a port capable of connecting an expansion unit, an interface connection between the computer and the expansion unit is attained using a specific cable having connectors at its two ends.
In this case, whether or not a cable is normally connected is visually checked.
However, a connection confirmation means of the expansion unit is not reliable since confirmation operations of a power supply state and a connector coupling state of the expansion unit are further required.
In recent years, in order to expand functions of a lap-top type compact portable computer, an expansion unit having a mechanism which fixes and docks the portable computer at a predetermined position in a usable state, and is bus-connected to an expansion bus connector of the computer, has been proposed. In this case, an operator must recognize based on an indication whether or not the expansion unit is normally connected when the power switch of the computer is turned on.
However, when the computer to be connected to the expansion unit has a resume function, the resume function may be enabled or disabled. For example, when a display card, an expansion memory card, or an HDD, (hard disk drive) card is connected to the expansion unit, the resume function is disabled. However, when a LAN card, an RS-232C card, or a printer card is connected to the expansion unit, the resume function is enabled. When the computer is started in a resume mode, an application software program is directly started, and a display screen immediately before the power-off is resumed. In a conventional system, if the expansion unit is connected when the resume mode is set, the expansion unit cannot be connected. However, in some cases, connection of the expansion unit is permitted even in the resume mode, as described above. In such a case, connection of the expansion unit is preferably informed to an operator. However, when a connection confirmation message displayed, a displayed portion of the resume screen is undesirably broken.
The U.S. application (application Ser. No. 578,533 now abandoned, filing date: Apr. 7, 1990, title of the invention: computer system capable of connecting expansion unit) by the same assignee discloses a system which comprises an expansion interface for connecting external I/O devices, and also comprises registers for storing data for enabling or disabling internal I/O devices, and a circuit for forcibly disabling chip selection of an LSI serving as a core of the I/O interface in accordance with the contents of the registers. Furthermore, the above-mentioned application discloses a power supply control system for an expansion unit having a connection port capable of detachably connecting a portable computer, which system comprises a power supply switch, a portable computer power supply circuit for supplying an operation power supply voltage to the portable computer connected to the connection port when the switch is turned on, a detection circuit for receiving a specific output signal from the portable computer connected to the connection port, and detecting that the portable computer is set in an operation enable state upon reception of the power supply voltage, and an expansion unit power supply circuit for supplying an operation power supply voltage to its own internal circuits in response to a detection signal from the detection circuit. Moreover, the application also discloses a connection control mechanism for an expansion unit, which mechanism on the expansion unit side comprises an external device connector provided to a portable computer, an interface circuit for the connector, a means for enable/disable-controlling the interface circuit, and a means for out putting device identification data, and which mechanism on the portable computer side comprises a means for enable/disable-controlling the interface circuit for the external device connector, a means for loading and recognizing the device identification data from the expansion unit, and a means for, when the device identification data is recognized, disabling the interface circuit of the external device connector, and enabling the interface circuit of the expansion unit.
In addition, the above-mentioned application discloses a portable computer system which comprises a portable computer main body, an expansion unit connected to the main body via a bus connector, a register for storing data for permitting/inhibiting use of internal I/O ports of the main body, a means for, when the expansion unit is connected to the main body, checking whether or not an address of an I/O port used by the expansion unit is present in the main body, and a means for, when the expansion unit is connected to the main body, and it is determined that the address of the I/O port used by the expansion unit is present in the main body, inhibiting use of I/O ports by the main body via the register.